Nathan House wrote:
> Hello,
>
> I'm a student and am interested in doing a project involving Ethernet.=20
You don't say what level of student you are, in what subject, how=20
competent you are or what the project is planning to do. Getting a=20
student project right is often a matter of balancing how much you "do=20
yourself" vs how much you "buy in". Doing stuff yourself is needed to=20
get marks but if you try and do everything yourself you can fail at the=20
project goals.
> I'm
> wanting to use a PIC18 microcontroller and it appears there are two with
> built-in Ethernet controllers:
>
> PIC18F66J60
> PIC18F67J60
>  =20
> They appear to be essentially the same, with the only difference being th=
e
> second one having more program memory.
>
> Do you think it would be better to use one of the microcontrollers with
> built-in Ethernet, or to interface another PIC18 microcontroller with an
> external Ethernet controller?
>  =20
It depends, there are several considerations

Do you plan to do the whole project on demo boards or will you be making=20
boards of your own? If the latter do you have the ability (on both the=20
PCB fabrication and soldering side) to reliablly work with 0.5mm pitch=20
parts? If not then you should probablly rule out those chips now.

> One disadvantage I can think of with using one of the above PIC18
> microcontrollers is that I would probably have to use an Ethernet
> stack/framework on the microcontroller, which might take up a lot of the
> processing power and make the software a lot more complex.
>  =20
A TCP/IP stack on a PIC18 micro is going to dominate your program.=20
Whether this is a problem depends very much on what exactly you are=20
doing. This will apply if you use a PIC with built in ethernet. It will=20
also apply if you use a PIC18 with a chip like the enc28j60

another option is to find an intelligent module that handles all the=20
TCP/IP stuff for you. Downside of this approach is that it will be=20
significantly more expensive and give you significantly less control=20
over how the ethernet is used. Again whether this matters depends very=20
much on your application.
> Could anyone give me some advice on what approach I should take?
>  =20
Not without more details.
--=20
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